The present invention relates to a marking film. More specifically, the invention relates to an improved marking film which can be transferred and adhered onto articles having rugged surfaces and steeply curved three-dimensional surfaces, favorably and with ease, without developing poor appearance caused by the entrapment of air bubbles at the ends of the film when an over-clear coating is applied onto the marking film. The invention also relates to a composite marking film comprising a combination of the marking film and the application film, exhibiting excellent effects of the marking film and enhancing the workability. The invention, therefore, can be advantageously used for adhering the marking film having a predetermined shape or ornament appeal (hereinafter referred to as xe2x80x9cmarking componentxe2x80x9d) onto articles such as automobiles, motorcycles, etc. and onto any other articles.
In order to assist the operation for transferring and adhering a marking film onto an article having curved surfaces and rugged portions, there have heretofore been used various types of transfer-assisting members called application films or application tapes. Japanese Unexamined Patent Publication (Kokai) No. 6-51702 discloses an application tape which can be transferred onto a desired article by peeling an ornamental adhesive sheet of a predetermined shape off a peel member, the base member of the tape having a 2% modulus value of 3 to 4 kg/15 mm of width and an elongation percentage at breakage of not smaller than 50% when the tension speed is 0.2 m/min.
Japanese Unexamined Patent Publication (Kokai) No. 7-138540 discloses an application film for a marking sheet having an adhesive layer formed on one surface of a base member of a thermoplastic resin and is used for applying a marking sheet, wherein the base member is more flexible than the marking sheet and has rich rubbery elasticity. Desirably, the base material of the application film is a soft vinyl chloride resin. Besides, the film desirably has a 10% modulus of 1.5 to 2.5 g/25 mm of width, a maximum elongation of 150 to 300% and a thickness of 50 to 100 xcexcm. The adhesive layer has a thickness of 10 to 20 xcexcm.
In recent years, however, it has been desired to stick the marking film onto ever steeply curved portions in the field of armoring such as, fuel tanks of motorcycles, fenders, etc. However, such requirements cannot be sufficiently met by the application films disclosed in the above-mentioned Unexamined Patent Publications. That is, on the portions of complex shapes such as fuel tanks, fenders, etc., the sticking operation must be carefully carried out so that wrinkles will not develop and air bubbles will not be entrapped, particularly, as the areas of such portions increase, resulting in a great decrease in the sticking operation efficiency, In order to improve the efficiency of sticking operation, it can be contrived to decrease the thickness of the marking film to cope with to various curved shapes or, in other words, to enhance the xe2x80x9cability for tracing curved surfacesxe2x80x9d. However, such a thin film is likely to be damaged during the work and, besides, loses the so-called xe2x80x9cstiffnessxe2x80x9d, deteriorating the workability, causing the positioning to become complex and often permitting the films to be adhered to each other during the work. Moreover, despite the operation is carefully done, wrinkles develop and air bubbles are inevitably entrapped. Besides, due to a complex shape of a portion where the film is to be stuck, the marking film after stuck is often damaged despite it was carefully stuck.
Moreover, in order to further improve the ornamental appeal or to protect the marking film applied to the article from being rubbed or peeled, an over-clear coating is often applied onto the marking film. Here, a problem stems from a step formed at the end of the film. When the marking film is thick, air bubbles are entrapped in the stepped portions to deteriorate appearance. Or, it often becomes necessary to stick the marking film all over again.
The present invention provides an improved marking film that is free from one or more of the above-mentioned problems inherent in the prior art. The present marking film can be transferred and adhered onto articles having rugged surfaces and steeply curved three-dimensional surfaces favorably and with ease. The present marking film does not cause the appearance to be deteriorated that stems from the entrapping of air bubbles at the ends of the film.
According to one aspect of the present invention, there is provided a marking film having a marking component to be transferred onto an article via an adhesive layer, wherein a total thickness of the marking film is in the range of from about 50 xcexcm to about 300 xcexcm, and the modulus of elasticity thereof is in the range of from about 2 kgf/mm2 to about 25 kgf/mm2 as measured under a condition where the marking film is elongated at a tension speed of 300 mm/min. into an elongation percentage in the range of from 0 to about 10%.
According to another aspect of the present invention, there is provided a composite marking film comprising a marking film having a marking component to be transferred onto an article via an adhesive layer, and an application film used as a transfer-assisting member when the marking film is to be transferred onto the article, wherein the modulus of elasticity of the composite marking film is in the range of from about 2 kgf/mm2 to about 28 kgf/mm2 as measured under a condition where the composite marking film is elongated at a tension speed of 300 mm/min. into an elongation percentage in the range of from 0 to about 10%.
The present inventors have conducted study in an attempt to solve the problems of the conventional application films or of the marking films used in combination therewith, as described above in the Background section, have discovered the fact that the problems can be solved upon improving the marking film rather than the application film and, particularly, upon improving the properties of the marking film, and have thus completed the marking film of the present invention.
As a result of the study conducted thus far, the study group of the present inventors has accomplished an application film as disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 10-287849. This application film is used as an intermediate transfer member when the marking member is to be adhered onto the article, and comprises a base member and an adhesive layer formed on one surface of the base member and can be adhered to the marking member, the base member having a 10% modulus strength of from 0.3 to 1.6 kgf/25 mm, a 10% modulus stress of from 0.1 to 0.8 kgf/mm2, a 100% modulus stress of from 0.7 to 2.5 kgf/mm2, and a rate of change in the modulus stress of not smaller than 0.3 when measured at a tension speed of 200 mm/min. in compliance with the standards stipulated under Japanese Industrial Standard (JIS)-K7127. Owing to particular properties of the base member that is used, the application film exhibits flexibility, rubbery elasticity and stiffness which are well balanced, and can be advantageously used as an intermediate transfer member at the time when the marking member is to be adhered, particularly, onto steeply curved three-dimensional surfaces of the articles. In using the application film, the inventors have forwarded the study concerning which marking member or, in other words, which marking film would be effective when the article has steeply curved three-dimensional surfaces, and have discovered that the marking member having suitable degrees of flexibility and rubbery elasticity is desirable. According to the present invention, the thickness and the modulus of elasticity at an elongation percentage of from 0 to 10% of the marking film are limited to lie within particular ranges, making it possible to improve the ability for tracing the three-dimensional curved surfaces. Even when the marking film is accompanied by the application film, the modulus of elasticity of the whole film at an elongation percentage of from 0 to 10% is limited to lie within a particular range to obtain the same effect. In addition, according to the present invention, the degree of ability for tracing the curved surfaces can be easily estimated from a formula of a primary function as will be described later in detail. Upon imposing limitation on the thickness of the marking film, furthermore, the over-clear coating can be applied without causing any trouble after the marking film has been stuck. According to the application film disclosed in the above-mentioned Japanese Unexamined Patent Publication (Kokai) No. 7-138540, it is essential to use a hard marking sheet having flexibility and rubbery elasticity inferior to those of the application film, which is contrary to those of the present invention.
Besides, the present inventors have discovered that the application film used in combination therewith plays an important role of maximizing the excellent action and effect exhibited by the marking film, and have completed the composite marking film of the present invention to obtain excellent effect stemming from the combination of the two films.